The present invention relates to a semiconductor device and particularly to a technique which can be effectively applied to the power supply circuit technology.
For example, a DC—DC converter (DC to DC converter) circuit is used as a power supply circuit for driving a CPU (Central Processing Unit) of an electronic device such as a personal computer, server or gate machine or the like. A composite power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) of the DC—DC converter discussed by the inventors of the present invention includes a power MOSFET circuit for switching and a power MOSFET circuit as a rectifier circuit. Respective circuits are separately packaged and individually mounted on a wiring substrate.